linux-kernel - [tip:smp/hotplug] KVM/PPC/Book3S HV: Use cpuhp_setup_state_nocalls

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Date:   Thu, 20 Apr 2017 04:21:55 -0700
From:   tip-bot for Sebastian Andrzej Siewior <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     mpe@...erman.id.au, bigeasy@...utronix.de, peterz@...radead.org,
        mingo@...nel.org, benh@...nel.crashing.org,
        linux-kernel@...r.kernel.org, rostedt@...dmis.org, hpa@...or.com,
        tglx@...utronix.de, agraf@...e.com
Subject: [tip:smp/hotplug] KVM/PPC/Book3S HV: Use
 cpuhp_setup_state_nocalls_cpuslocked()

Commit-ID:  2fd231725b835f38e70fbda0842de57e330cd147
Gitweb:     http://git.kernel.org/tip/2fd231725b835f38e70fbda0842de57e330cd147
Author:     Sebastian Andrzej Siewior <bigeasy@...utronix.de>
AuthorDate: Tue, 18 Apr 2017 19:04:49 +0200
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Thu, 20 Apr 2017 13:08:52 +0200

KVM/PPC/Book3S HV: Use cpuhp_setup_state_nocalls_cpuslocked()

kvmppc_alloc_host_rm_ops() holds get_online_cpus() while invoking
cpuhp_setup_state_nocalls().

cpuhp_setup_state_nocalls() invokes get_online_cpus() as well. This is
correct, but prevents the conversion of the hotplug locking to a percpu
rwsem.

Use cpuhp_setup_state_nocalls_cpuslocked() to avoid the nested call.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: kvm@...r.kernel.org
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Benjamin Herrenschmidt <benh@...nel.crashing.org>
Cc: Steven Rostedt <rostedt@...dmis.org>
Cc: kvm-ppc@...r.kernel.org
Cc: Michael Ellerman <mpe@...erman.id.au>
Cc: linuxppc-dev@...ts.ozlabs.org
Cc: Alexander Graf <agraf@...e.com>
Link: http://lkml.kernel.org/r/20170418170552.946155801@linutronix.de

---
 arch/powerpc/kvm/book3s_hv.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 1ec86d9..df7117c 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -3336,10 +3336,10 @@ void kvmppc_alloc_host_rm_ops(void)
 		return;
 	}
 
-	cpuhp_setup_state_nocalls(CPUHP_KVM_PPC_BOOK3S_PREPARE,
-				  "ppc/kvm_book3s:prepare",
-				  kvmppc_set_host_core,
-				  kvmppc_clear_host_core);
+	cpuhp_setup_state_nocalls_cpuslocked(CPUHP_KVM_PPC_BOOK3S_PREPARE,
+					     "ppc/kvm_book3s:prepare",
+					     kvmppc_set_host_core,
+					     kvmppc_clear_host_core);
 	put_online_cpus();
 }